1. Field of Invention
The present invention relates to a printing method, a printer driver, and a system for printing a color loss determination stamp enabling easy verification of color loss (any printable color not printing) when printing in any print mode on a printer having a plurality of print modes.
2. Description of the Related Art
Stamps such as COPYING PROHIBITED, IMPORTANT, URGENT, and CONFIDENTIAL indicating how a document can be used are sometimes printed when print data created by a computer software application is printed using a connected printer. The printer driver provides the ability to print such stamps (see Japanese Patent No. 3419320).
Such stamps are printed by merging image data for the stamp with the print data created by the software application and printing the merged data (see Japanese Unexamined Patent Appl. Pub. JP-A-H08-18767).
One type of stamp also printed by inkjet printers is a color loss determination stamp, a stamp that enables the user to determine if the plural printable colors of ink are printing normally. An example of a color loss determination stamp printed by a four-color inkjet printer is described next.
The letters NG (referred to below as a “color loss determination unit”) are printed in black ink in a prescribed printing area, and other printing areas (the background) are printed by overlaying three colors of ink, typically cyan, magenta, and yellow, producing a composite black. If all colors of ink, that is, black, cyan, magenta, and yellow in this example, print normally, the printed color of the color loss determination unit and the printed color of the background will be the same color (black). Thus, the entire printing area will be printed the same color, and the letters NG will be indistinguishable from the background.
However, if at least one color of ink does not print, that is, color loss occurs, the printed color of the color loss determination part and the printed color of the background will be different and the letters NG will be readable. Determining color loss is thus made possible.
The color loss determination stamp is a bitmap image for determining color loss. The bitmap image data for the color loss determination unit contains dots that are printed using black ink, and the bitmap image data for the background contains dots that are printed a composite black using the three colors cyan, magenta, and yellow. Both groups of dots are controlled so that they are printed in the same color (e.g. black or a shade of gray).
Printers and printer drivers have plural print modes optimized for the type of printing paper, the print resolution, and printing speed of the printer. The print modes can be selected by the printer driver. One print mode is selected from among the plural print modes for printing. Examples of the print modes provided in an inkjet printer include a plain paper print mode, a glossy paper print mode, and a matte paper print mode for use with different types of paper. Each of these print modes can also be set to an image quality priority mode or a printing speed priority mode.
The color loss determination stamp printed on an inkjet printer that has plural print modes is printed based on bitmap image data for color loss determination that is stored in the printer driver. While the printed color in the color loss determination part and the printed color in the background are adjusted to produce the same color in a particular print mode, if the same image data is printed in a different print mode, the color printed in the color loss determination part and the color printed in the background may not be the same. This is because the number of ink shots discharged to print each color differs according to the print mode.
For example, if the bitmap image data for one color loss determination stamp is intended for printing in the speed priority mode of the plain paper print mode, the printed color of the color loss determination part and the printed color of the background will match, and the entire color loss determination stamp will be printed the same black (or shade of gray) color. However, if the same print data is printed using the image quality priority mode of the glossy paper print mode, the dots printed in the background portion will not be the same black as the color loss determination area. The background portion may be a lighter gray or a color such as a shade of red or green. The letters NG will therefore be legible even though none of the colors are actually missing, and the user will mistakenly determine that color loss has occurred.